Zones B and C
The legacy moderate- and low-risk designations that predate Zone X — retained on older, un-modernized flood maps.
fldzone = 'B' · fldzone = 'C'
Risk tier: Moderate to low — outside the Special Flood Hazard Area (SFHA).
Zones B and C are the historical designations that FEMA used before the map-modernization program replaced them with Zone X. They still appear on older FIRM panels that have not been converted, so both values can occur in the dataset.
The mapping to modern zones
| Legacy | Modern equivalent | Meaning |
|---|---|---|
B | shaded X | Between the 1% and 0.2% annual-chance floodplains (the 500-year floodplain), or 1%-annual-chance areas with average depths under 1 foot / drainage areas under 1 square mile, or areas protected by a levee from the base flood. |
C | unshaded X | Areas of minimal flood hazard, outside the 0.2%-annual-chance floodplain. |
Building and insurance implications
- Both are outside the SFHA, so flood insurance is not federally mandated — though lenders may require it, and lower-cost Preferred Risk policies are available. Zone B (shaded-X-equivalent) still represents a meaningful residual risk.
- No SFHA elevation requirements apply.
zonesubty values
Legacy B/C polygons generally carry no subtype; the modern shaded/unshaded distinction is captured by the X subtypes described on the Zone X page.
In the data
| Column | Value |
|---|---|
fldzone | B or C |
staticbfe | NULL |
zonesubty | usually empty |
firmid / firmdate | source FIRM panel and effective date (often older) |
-- Legacy moderate/low-risk designations
SELECT lrid, parceladdr, fldzone, firmdate
FROM lr_parcel_us
WHERE fldzone IN ('B', 'C');Prefer firmdate awareness
Because B and C only survive on un-modernized panels, parcels carrying them usually have an older firmdate. If you are analyzing current risk, treat B as shaded X and C as unshaded X.